1. Field of the Invention
The present invention relates to an electric-component supplying unit which supplies electric components (e.g., electronic components) from an electric-component tape and in particular to the art of supplying a plurality of sorts (e.g., types) of electric-component tapes.
2. Related Art Statement
There is known an electric-component ("EC") tape which includes a carrier tape and holds a plurality of electric components ("ECs") at a predetermined pitch in a lengthwise direction of the carrier tape, and an EC supplying ("EC-supply") unit which feeds the EC tape and supplies the ECs, one by one, from the EC tape. The known EC-supply unit includes a frame including a tape-guide portion which guides the EC tape; and a feeding device which feeds, in the lengthwise direction, the EC tape being guided by the tape-guide portion, and positions the ECs, one by one, at a predetermined EC-supply position where each EC is supplied to an EC receiving device as an object device.
There are known a plurality of sorts of EC tapes each of which can be supplied by the EC-supply unit and which are of different types, have different dimensions (e.g., different widths or different thicknesses), or hold ECs at different pitches (hereinafter, referred to as the "EC-hold pitch(es)"). For example, there are known different types of EC tapes such as an embossed-carrier-type ("ECT") one, a punched-carrier-tape ("PCT") one, and a lead-wire-terminal-taped-type ("LWTT") one. The ECT EC tape includes (a) a carrier tape which includes a pair of widthwise opposite end portions each extending in a lengthwise direction thereof, and a plurality of embossed portions each projecting downward from between the two end portions and each accommodating one EC, and (b) a top cover tape which is adhered to the carrier tape to close respective upper openings of the embossed portions. The PCT EC tape includes (c) a carrier tape which includes (c1) a base tape which is formed of, e.g., paper or synthetic resin and which has a plurality of through-holes formed through the thickness thereof and (c2) a bottom cover tape which closes respective lower openings of the through-holes to provide a plurality of EC accommodating pockets each accommodating one EC, and (d) a top cover tape which is adhered to the carrier tape to close respective upper openings of the through-holes or the EC accommodating pockets. The LWTT EC tape may be one which includes a carrier tape which is provided by a tacky tape and which holds a plurality of ECs whose respective lead-wire terminals are adhered thereto, or one which includes a carrier tape which includes a tacky tape and a support sheet and which holds a plurality of ECs whose respective lead-wire terminals are adhered thereto. Each type of EC tapes include different sorts of EC tapes having different widths, different thicknesses, or different EC-hold pitches.
There have been various proposals to deal with different sorts of EC tapes. For example, U.S. Pat. No. 5,588,614 discloses an EC-supply unit which can supply ECs from different sorts of ECT EC tapes having different widths. The disclosed EC-supply unit employs at least one width changing block for changing the distance between two support members which can support the two end portions of the carrier tape of one sort of ECT EC tape, respectively. More specifically described, the prior EC-supply unit includes a frame, and two support rails as the two support members that are fixed to the frame and whose respective upper surfaces provide respective support surfaces which can support and guide the two end portions of the carrier tape of the one sort of ECT EC tape. One width changing block is placed in close contact with the inner side surface of 6ne of the two support rails, so that the distance between the two fixed support rails is decreased to a value which can support the two end portions of the carrier tape of another sort of ECT EC tape having a smaller width. In the case where two or more width changing blocks having different widths are employed, the EC-supply unit can supply three or more sorts of ECT EC tapes having different widths.
The above-identified U.S. Pat. No. 5,588,614 additionally discloses another EC-supply unit which includes a fixed support rail and a movable support rail which is movable toward, and away from, the fixed rail. In this case, the distance between the two support rails can be adjusted by moving the movable rail relative to the fixed rail, depending upon the width of an ECT EC tape to be supplied.
Thus, each of the EC-supply units disclosed in the U.S. patent can deal with different sorts of ECT EC tapes having different widths, but cannot deal with different types of EC tapes, e.g., two or all of the ECT, PCT, and LWTT EC tapes. Conventionally, different types of EC tapes have been dealt with by corresponding exclusive types of EC-supply units. For example, an ECT EC tape is supplied by an exclusive EC-supply unit which includes two support rails for supporting the two end portions of the carrier tape thereof and a groove provided between the two rails for allowing the embossed portions of the carrier tape to pass therethrough; and a PCT EC tape is supplied by an exclusive EC-supply which includes a support surface which supports and guides the lower surface of the bottom cover tape thereof.
Meanwhile, there is also known an EC-supply unit employing a frame which includes a cover member for preventing an EC tape from moving up off the frame. It is practiced to use the cover member to position the EC tape in the widthwise direction thereof.
However, the frame of each of the EC-supply units disclosed in the U.S. patent must have a width corresponding to the widest one of the different sorts of EC tapes which are to be supplied by the each EC-supply unit. Thus, for example, in the case where a plurality of EC-supply units are attached to a table such that respective EC-supply portions of the units are arranged along a straight line, the pitch at which the units are attached to the table must correspond to the widest one of the different sorts of EC tapes that have different widths. Therefore, even when the EC-supply units supply EC tapes having a smaller width, the pitch cannot be changed. Since, in this case, the pitch is too large and only a small number of EC tapes can be attached to the table, the efficiency of supplying of ECs is lowered.
In addition, the second prior EC-supply unit which employs the fixed and movable support rails suffers from the problem that the structure of the unit is too complex.
Moreover, in the case where different types of EC tapes are dealt with by corresponding exclusive types of EC-supply units, many types of EC-supply units must be produced and accordingly the production cost thereof cannot be lowered by mass production.
Furthermore, the third prior EC-supply unit which employs the cover member for preventing the EC tape from moving off the frame, suffers from the problem that the EC-supply unit cannot deal with different sorts of EC tapes having different EC-hold pitches. The cover member must not interfere with an EC holder which takes and holds each EC from the EC tape at the EC-supply position, but needs to cover the EC located adjacent to the each EC being taken by the EC holder on an upstream side of the each EC in the EC-feed direction. However, if the cover member is provided at a position where the cover member allows the EC holder to take each EC at the EC-supply position, irrespective of whether the EC-hold pitch of each EC tape is great or small or whether a dimension of the each EC in the EC-feed direction is great or small, the cover member may not cover the upstream EC adjacent to the each EC, in the case where the EC-hold pitch is small or the dimension of the each EC is small.
The third prior EC-supply unit suffers from another problem that the EC-supply unit cannot deal with different sorts of EC tapes having different thickness values. Here, a thickness value of an EC tape is defined as the height of the upper surface of the EC tape as measured from one or more support surface of the frame that support and guide the EC tape. In order to supply different sorts of ECs having different thicknesses, from different sorts of EC tapes having corresponding different thicknesses, respectively, the EC-supply unit must be used with each of different sorts of cover members having corresponding different thicknesses which allow the different sorts of EC tapes to be fed while being supported on the support surface or surfaces of the frame, and which contact the respective upper surfaces of the different sorts of EC tapes to prevent the tapes from moving up off the frame. Thus, many sorts of cover members must be produced.